A 36-Pulse AC-DC Converter With DC Side Tapped Interphase Bridge Rectifier for Power Quality Improvement

Research on harmonic generation principle of series‐connected multi‐pulse rectifiers and optimization design method for main transformers

“…In Figure 7a, −40°≤ α ← 20°, according to the triangle theory and [13–22] it can be obtained that $$$$\begin{eqnarray} \frac{{{N_{\mathrm{Y}}}}}{{\sin {{120}^ \circ }}} &=& \frac{{{N_1}}}{{\sin ({{20}^ \circ } - \alpha )}} = \frac{{{N_2}}}{{\sin ({{40}^ \circ } + \alpha )}} = \frac{{{N_3}}}{{\sin ({{60}^ \circ } + \alpha )}}\nonumber\\ &=& \frac{{{N_4}}}{{\sin ( - \alpha )}} = \frac{{{N_5}}}{{\sin ( - {{20}^ \circ } - \alpha )}} = \frac{{{N_6}}}{{\sin ({{80}^ \circ } + \alpha )}} \end{eqnarray}$$$$where N Y is the equivalent turns number of the coordinates, N 1 , N 2 , N 3 , N 4 , N 5 and N 6 are the turns number of the transformer windings.…”

“…Table 5 shows the comparison between the proposed transformers and the transformers of the parallel‐connected MPRs of [14, 16, 22, 23, 26, 27, 29]. The transformers of [14] and [16] are the isolation type, while the transformers of [22, 23, 26, 27, 29] are the auto type.…”

“…In [22–31] the transformers are auto‐type. In [22–25] the transformers output two sets of three‐phase voltages with a 30° phase difference, and in [26–28] the transformers output three sets of three‐phase voltages with a 20° phase difference.…”

“…In [22–31] the transformers are auto‐type. In [22–25] the transformers output two sets of three‐phase voltages with a 30° phase difference, and in [26–28] the transformers output three sets of three‐phase voltages with a 20° phase difference. In [29–31] the transformers output two sets of five‐phase voltage with an 18° phase difference to perform 20‐pulse rectification.…”

“…Compared to the isolation type transformers, the kVA rating of the auto type transformers is reduced by about 60%. However, the rectifiers in [22–31] are all parallel‐connected MPRs, and there is no precedent for using series rectifiers.…”